Vscode-rust: RLS could not set RUST_SRC_PATH for Racer because it could not read the Rust sysroot.

[zanjs]

[Pzixel]

Why did you close it? How to fix it?

[Andrew-Webb]

@Pzixel - I fixed this by allowing VSCode to install the nightly toolchain components for Rust.

[Andrew-Webb]

Indeed, the Rust (rls) extension lists as one of its requirements:-

"A nightly Rust toolchain (the extension will configure this for you, with permission),"

[andradei]

@Andrew-Webb How do you allow VSCode to install the nightly toolchain? I have nightly already installed and the plugin doesn't ask me to install it...

[Andrew-Webb]

@andradei - When I first used it, RLS prompted me to install the nightly toolchain components. After I allowed it to, and restarted, the error "RLS could not set RUST_SRC_PATH for Racer because it could not read the Rust sysroot." went away.

I now see that with RLS 0.3.2 the extension no longer mentions the nightly toolchain as one of its requirements. The requirements are:-

• Rustup
• A Rust toolchain (the extension will configure this for you, with permission),
• RLS (currently rls-preview), rust-src, and rust-analysis components (the extension will install these for you, with permission).

Maybe you need to rustup update to update your toolchains, nightly or otherwise?

[andradei]

@Andrew-Webb I ran rustup update a lot this last time... I have stable and nightly toolchains installed. No dice.

[KaneGreen]

@Andrew-Webb I allowed vscode to configure Rust toolchain, rls-preview, rust-src, and rust-analysis but it took me a lot of time. So, I closed vscode and I wanna configure by myself. As you said, it doesn't need the nightly toolchain any more. So, I'm using stable-x86_64-pc-windows-msvc. However, the extension doesn't work, either.

[prycejs]

This issue seems to have changed now that nightly toolchain is not required.

Further, the current version of the VSCode extension that I just installed still kept offering to install the nightly toolchain, which I do not want.

Using the current version of the rls VSCode exension, 0.4.5, release 2018-06-03, I had to solve this problem in early June 2018 I did the following:

1. First, edit my VS Code settings to add the following entry in my user settings:

    "rust-client.channel": "stable"

You can also set "rust-client.logToFile" to true here if you want - that part is not strictly necessary - but it means that if or when rls fails you get a log file you can examine to see what went wrong to help you figure out the problem.

1. Restart VS Code

2. On restart, a popup offered to install RLS (but did not mention the nightly toolchain anymore. I chose yes.

After this, the VSCode extension appears to be working for me.

[MaxDesiatov]

Seems to me that "rust-client.channel": "stable" should be the default now that nightly is no longer a requirement.